Castles were powerful defensive structures but it was also the place which ordinary people associated with authority. They were important centres of administration and local government. Tax collectors, officers of the court and market traders could also be found within the walls of a castle.

The introduction of the Motte and Bailey castle following the Norman Conquest of 1066 fundamentally reshaped English society by acting as both a military garrison and an administrative tool. Before William the Conqueror, castles were rare; he initiated a massive building spree to maintain control over a hostile Anglo-Saxon population. These structures allowed a small number of Norman soldiers to dominate large geographical areas, effectively suppressing local rebellions. Economically and socially, castles accelerated the feudal system, as land was redistributed to loyal Norman barons who used these fortifications as bases for tax collection and legal administration. Castles also altered the landscape, often being built in strategic urban centers, which occasionally required the destruction of local homes. Over time, they transformed from wooden forts into massive stone symbols of Norman power, solidifying the new ruling elite and permanently changing the nature of warfare from open field battles to prolonged sieges.